The present invention relates to a method for extending a volume capacity when monitoring a storage system used for a computer system, in particular, when writing into the storage system from a host computer.
Generally speaking, a computer system comprises a host computer for executing jobs and a storage system for reading/writing data in response to directives of the host computer. The storage system has a plurality of disk drives for storing and reading data. The storage system provides a storage region to the host computer as a volume. The capacity of the volume can be extended at any time if necessary. For example, when the host computer uses up the volume provided by the storage system, the volume capacity can be extended by creating a storage region from an unused disk capacity in the storage system and by the host computer combining the storage region with the volume being used. Such a technique is called on-line volume extension.
Japanese Unexamined Patent Application Publication No. 2003-15915 describes a method in which a storage system creates a storage region from an unused region in a disk drive while the host computer is being on-line and dynamically adds the storage region to a storage region of a volume when the capacity of the volume in the storage system is running short due to writing from the host computer. Such a technique is called volume capacity automatic extension. By the volume capacity automatic extension, an on-line volume can be extended automatically without intervention of a storage manager.
According to the present invention, prior to creating a volume, a storage manager determines a characteristic corresponding to the way of use. When automatically extending a volume capacity, the storage system adds to the volume a storage capacity in a disk drive corresponding to the characteristic of the volume.
Thus, the present invention relates to a computer system having a storage system including a physical storage device, a host computer being connected to the storage system via a network and reading/writing data in a volume, and a management computer with an interface for connecting to the storage system and to the host computer via the network and for receiving a constitution change directive from a user, the storage system including a plurality of kinds of physical storage devices physically dividing into two segments or more the volume as a storage region used by the host computer, recording as constitution information the correspondence between each segment and the volume using the segment, recording the kind of physical storage device to be allocated to the volume, and selecting the physical storage device according to the kind of stored physical storage device for allocation of the segment when the host computer performs an I/O access to the volume.